1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 // <utility>
10 
11 // template<ValueType T, size_t N>
12 //   requires Swappable<T>
13 //   void
14 //   swap(T (&a)[N], T (&b)[N]);
15 
16 #include <utility>
17 #include <cassert>
18 #include <memory>
19 
20 #include "test_macros.h"
21 
22 
23 #if TEST_STD_VER >= 11
24 struct CopyOnly {
25     CopyOnly() {}
26     CopyOnly(CopyOnly const&) noexcept {}
27     CopyOnly& operator=(CopyOnly const&) { return *this; }
28 };
29 
30 
31 struct NoexceptMoveOnly {
32     NoexceptMoveOnly() {}
33     NoexceptMoveOnly(NoexceptMoveOnly&&) noexcept {}
34     NoexceptMoveOnly& operator=(NoexceptMoveOnly&&) noexcept { return *this; }
35 };
36 
37 struct NotMoveConstructible {
38     NotMoveConstructible() {}
39     NotMoveConstructible& operator=(NotMoveConstructible&&) { return *this; }
40 private:
41     NotMoveConstructible(NotMoveConstructible&&);
42 };
43 
44 template <class Tp>
45 auto can_swap_test(int) -> decltype(std::swap(std::declval<Tp>(), std::declval<Tp>()));
46 
47 template <class Tp>
48 auto can_swap_test(...) -> std::false_type;
49 
50 template <class Tp>
51 constexpr bool can_swap() {
52     return std::is_same<decltype(can_swap_test<Tp>(0)), void>::value;
53 }
54 #endif
55 
56 #if TEST_STD_VER > 17
57 constexpr bool test_swap_constexpr()
58 {
59     int i[3] = {1, 2, 3};
60     int j[3] = {4, 5, 6};
61     std::swap(i, j);
62     return i[0] == 4 &&
63            i[1] == 5 &&
64            i[2] == 6 &&
65            j[0] == 1 &&
66            j[1] == 2 &&
67            j[2] == 3;
68 }
69 #endif // TEST_STD_VER > 17
70 
71 int main(int, char**)
72 {
73     {
74         int i[3] = {1, 2, 3};
75         int j[3] = {4, 5, 6};
76         std::swap(i, j);
77         assert(i[0] == 4);
78         assert(i[1] == 5);
79         assert(i[2] == 6);
80         assert(j[0] == 1);
81         assert(j[1] == 2);
82         assert(j[2] == 3);
83     }
84 #if TEST_STD_VER >= 11
85     {
86         std::unique_ptr<int> i[3];
87         for (int k = 0; k < 3; ++k)
88             i[k].reset(new int(k+1));
89         std::unique_ptr<int> j[3];
90         for (int k = 0; k < 3; ++k)
91             j[k].reset(new int(k+4));
92         std::swap(i, j);
93         assert(*i[0] == 4);
94         assert(*i[1] == 5);
95         assert(*i[2] == 6);
96         assert(*j[0] == 1);
97         assert(*j[1] == 2);
98         assert(*j[2] == 3);
99     }
100     {
101         using CA = CopyOnly[42];
102         using MA = NoexceptMoveOnly[42];
103         using NA = NotMoveConstructible[42];
104         static_assert(can_swap<CA&>(), "");
105         static_assert(can_swap<MA&>(), "");
106         static_assert(!can_swap<NA&>(), "");
107 
108         CA ca;
109         MA ma;
110         static_assert(!noexcept(std::swap(ca, ca)), "");
111         static_assert(noexcept(std::swap(ma, ma)), "");
112     }
113 #endif
114 
115 #if TEST_STD_VER > 17
116     static_assert(test_swap_constexpr());
117 #endif // TEST_STD_VER > 17
118 
119   return 0;
120 }
121